You guessed it, we’re going to be working with the command line. I’ll show you how to disable IPv6 on Red Hat- and Debian-based distributions.

Here’s how to disable the protocol on a Red Hat-based system:

Open a terminal window. Change to the root user. Issue the command :

sysctl -w net.ipv6.conf.all.disable_ipv6=1

Issue the command :

sysctl -w net.ipv6.conf.default.disable_ipv6=1

To re-enable IPv6, issue the following commands:

sysctl -w net.ipv6.conf.all.disable_ipv6=0

sysctl -w net.ipv6.conf.default.disable_ipv6=0

Here’s how to disable the protocol on a Debian-based machine.

1. Open a terminal window.

2. Issue the command sudo nano /etc/sysctl.conf

3. Add the following at the bottom of the file:

net.ipv6.conf.all.disable_ipv6 = 1
 
net.ipv6.conf.default.disable_ipv6 = 1
 
net.ipv6.conf.lo.disable_ipv6 = 1

4. Save and close the file.

5. Reboot the machine.

To re-enable IPv6, remove the above lines from /etc/sysctl.conf and reboot the machine.